ADHERING CHLOROSULFONATED POLYETHYLENE TO NON-POLAR POLYOLEFINIC ELASTOMERS

Abstract: A method for achieving adhesion between an adhesive composition and a non-polar polyolefinic elastomer. The adhesive composition is based on a chlorosulfonated polyolefin having a chlorine content between about 5 and 30 percent. The adhesive composition is contacted with the surface of the non-polar polyolefinic elastomer at an elevated temperature so as to effect adhesion. The specific chlorine content of the chlorosulfonated polyolefins allows them to be utilized effectively without relying on traditional aromatic nitroso compounds or their precursors.

Description: Description "Adhering chlorosulfonated polyethylene to non-polar polyolefinic elastomers" Technical Field This invention relates to a method for achieving adhesion between certain adhesive compositions and certain polyolefinic elastomers. More particularly, the invention relates to a method for achieving adhesion between certain chlorosulfonated polethylenes and non-polar polyolefinic elastomeric materials. Background Art Ethylene-propylene-diene terpolymers (EPDM) and isobutylene- isoprene copolymers (IIR) are generally recognized as among the least polar of vulcanizable rubbery materials and have correspondingly been found to be the most difficult to bond or to achieve adhesion to through the agency of organic coatings. Consequently much effort has been directed by the suppliers of adhesives and related products to the development of suitable and effective adhesives and primers for these non-polar elastomers. This effort has been ongoing in the case of EPDM compounds for approximately 30 years and for IIR for more than 40 years. Representative adhesive or primer compositions developed over the years for bonding olefinic elastomers have been based more often than not on halogenated elastomers or other halogen-containing film- forming resins. These compositions typically contain an aromatic nitroso compound such as dinitrosobenzene or a precursor of an aromatic nitroso compound such as quinone dioxime. The aromatic nitroso compounds or precursors are believed to act as crossbridging agents so as to form a linkage between the adhesive composition and the olefinic substrate being bonded. For vulcanization bonding of olefinic elastomers such as EPDM to metal, adhesive formulations along these lines are offered by several adhesives suppliers. (See current adhesive product lists and guides of Lord Corporation, Elastomer Products Division [CHEMLOK adhesives]; Morton Chemical Corporation, Adhesives Division [THIXON adhesives]; Metallgesellschaft [MEGUM adhesives].) Such adhesives are typically deployed over a suitable metal primer. The metal primers suitable for use under adhesives for olefinic elastomers typically contain highly halogenated or halogen-containing resins along with appropriate thermosetting resins and various inorganic fillers. (Appropriate primers also are cited in the above guides and lists of commercially available products.) Typical commercial applications for EPDM elastomer-to-metal assemblies include anti-vibration or anti-shock mounts and bushings for motor vehicles. EPDM is particularly well suited for assemblies that must do service at elevated temperatures and/or in the presence of oxygen. Unlike EPDM, other widely used diene elastomers are prone to damage through oxidative scission of the polymer backbone, and in the case of natural rubber, to thermal reversion as well. Another important automotive application for EPDM elastomer- to-metal assemblies is that of extruded EPDM window channeling or metal-supported weather strips. Sheet metal (aluminum and gal¬ vanized steel are typical) is normally coated with an appropriate primer and adhesive overcoat, dried and slit into continuous window channel substrate form. Compounded but uncured EPDM is then extruded onto the coated metal and bonded with heat that also drives the EPDM vulcanization reaction. Adhesives and primers for bonding EPDM window channeling are generally very similar to those selected for EPDM mount or bushing fabrication and generally comprise at least one halogenated or halogen-containing film-former and an aromatic nitroso compound or precursor. Adhesive compositions of this type are described in U. S. Pat. No. 3,282,883 (DeCrease, Shafer), and also in U.S. Pat. No. 4,119,587 (Jazenski, Manino). Both patents cite the use of chloro¬ sulfonated polyethylene as a suitable halogen-containing film-former, and dinitrosobenzene as a necessary ingredient. Other automotive applications of EPDM take advantage of the uncured elastomer's good extrudability and of its excellent degradation resistance when vulcanized. In window channel applications it is often specified by the automobile manufacturer that the elastomer profile should be flocked, i.e. with polyester textile fibers. The protruding closely-packed fibers of a flocked extrusion enable a good seal to window glass that will be rolled up and down so that dirt and other refuse cannot enter the automobile door's interior. The flocked elastomer surface also presents little or no undesirable friction as the window glass moves against it. Effective adhesives for bonding textile flock fibers to unvulcanized or vulcanizing EPDM extrusions have been developed over the past several years. Two general methods are employed under the current state-of-the-art. The first approach makes use of primer compositions which readily bond to the EPDM under the influence of heat. An elastomeric flock adhesive of the urethane type can then be applied to the primed EPDM to result in a well-bonded flocked surface. Typical primer compositions, like the formulations for bonding EPDM to metal, are based on one or more halogen-containing film-formers and an aromatic nitroso compound or precursor. EPDM primer compositions used for flocking of extrusions can also be employed where it is desired to coat an elastomeric EPDM substrate. For example, EPDM may be coated for aesthetic purposes such as white coatings for the EPDM sidewall of tires. Primer compositions for bonding EPDM are commercially available from LORD Corporation under the trade names CHEMLOK 236, CHEMLOK 459, andTS3320-19. The second approach for flocking EPDM extrusions involves adhesive compositions of the urethane type which adhere directly to the untreated EPDM surface. Adhesive formulations along such lines are the subject of U. S. Pat. No. 4,535,121 (Oezelli, Hofimann). In order to achieve direct bonding to the unvulcanized or vulcanizing EPDM substrate, the urethane type compositions typically rely on the use of aromatic nitroso compounds or precursors of the same type as employed in EPDM-to-metal adhesives. Although the present state-of-the-art offers adequately adhering EPDM primer, adhesive and coating compositions, the existing formulations do have deficiencies and disadvantages. One difficulty with certain state-of-the-art adhesives is that of blisters forming under the extruded EPDM after bonding. These blisters are believed to be due to decomposition products of the aromatic nitroso compounds used in such formulations. Also inherent in the use of aromatic nitroso compounds are staining problems that arise due to the aromatic chromophoric nature of these materials. For example, dinitrosobenzene or its residues in flock adhesives may come into contact with the light-colored paintwork of an automobile and cause it to be stained irreversibly yellow or brown. Coating primers based on this material can also result in staining of white or other light colors of overlaid coatings. Another disadvantage of bonding or priming compositions, which are totally ineffective without aromatic nitroso compounds, is the high temperature requirement for their thermal activation. It is often undesirable or inconvenient to expose the assembly to a high temperature in order to achieve adhesion. Many of these disadvantages and undesirable performance features of present state-of-the-art compositions make it apparent that there is a definite need for adhesive formulations for bonding non¬ polar polyolefinic elastomers such as EPDM or IIR that would not require the use of aromatic nitroso compounds. Disclosure of Invention It has now surprisingly been discovered that certain chlorine- containing polyolefins are able to bond non-polar polyolefinic elastomers directly, and under the influence of heat, without the need for aromatic nitroso compounds. Thus extremely simple adhesive or primer formulations have been demonstrated that are effective either with vulcanized or vulcanizing non-polar polyolefinic elastomers. The present invention is based on the unexpected discovery that chlorosulfonated polyolefins having a chlorine content not greater than about 30 percent have an unusual and substantial affinity for non-polar polyolefinic elastomers. The present invention therefore relates to a method for achieving adhesion between an adhesive composition and a non-polar polyolefinic elastomer comprising contacting the adhesive composition with the surface of the non-polar polyolefinic elastomer at an elevated temperature sufficient to effect adhesion wherein the adhesive composition consists essentially of a chlorosulfonated polyolefin having a chlorine content of between about 5 and 30 percent. Best Mode for Carrying Out the Invention The present invention relates to a method for achieving adhesion between an adhesive composition and a non-polar polyole¬ finic elastomer comprising contacting an adhesive composition with the surface of the non-polar polyolefinic elastomer at an elevated temperature sufficient to effect adhesion wherein the adhesive composition consists essentially of a chlorosulfonated polyolefin having a chlorine content of between about 5 and 30 percent. The non-polar polyolefinic elastomers (NPP elastomers) suitable for utilization in the method of the present invention can essentially be any elastomeric olefin copolymer which has residual carbon-to-carbon unsaturation. Examples of NPP elastomers include ethylene- propylene-diene terpolymers (EPDM), isobutylene-isoprene copolymers (IIR), and elastomeric trans-polypentene copolymers, with EPDM and IIR being preferred. As is known in the art, EPDM is prepared from ethylene monomers, propylene monomers and diene monomers. The diene monomers utilized to prepare the EPDM may be any diene monomer copolymerizable with ethylene or propylene monomers so as to provide residual unsaturation, preferably residual side-chain unsaturation in the resulting polymer. Examples of diene monomers include 1,4-hexadiene, ethylidene norbornene, and dicyclopentadiene, with 1,4-hexadiene and ethylidene norbornene being preferred. The NPP elastomer can be in essentially any form that will enable it to receive an adhesive composition. For example, the NPP elastomer can be in the form of a block, strip, or sheet such as obtained by transfer or injection molding of the uncured NPP elastomer. The chlorosulfonated polyolefin useful in the method of the present invention can essentially be any olefin polymer or copolymer that has been simultaneously post-chlorinated and post-chlorosul- fonated in solution, dispersion, or melt form, and thereby containing up to about 3 percent sulfur and up to about 30 percent chlorine. Examples of chlorosulfonated polyolefins useful in the present invention include chlorosulfonated polyethylene, chlorosulfonated polypropylene, chlorosulfonated ethylene-propylene copolymer, chloro¬ sulfonated trans-polypentene, and chlorosulfonated polyisobutylene, with chlorosulfonated polyethylene being preferred. Chlorosulfonated polyolefins are commercially available and can be prepared according to methods well known in the art, such as by dissolving polyethylene in carbon tetrachloride and subjecting the resulting solution to a mixture of chlorine gas and sulfur dioxide gas under high temperature and high pressure. The carbon tetrachloride is then removed to produce a powder of chlorosulfonated polyethylene. Various chlorosulfonated polyolefins are also commercially available from E. I. du Pont de Nemours & Co. under the trade names HYPALON and ACSIUM. The chlorosulfonated polyolefin can be in the form of a latex for use in an aqueous composition. Latices of chlorosulfonated polyolefins are commercially available and can be prepared according to methods known in the art such as by dissolving the chlorosulfonated polyolefin in a solvent and adding a surfactant to the resulting solution. Water is then added to the solution under high shear to emulsify the polymer. The solvent is then stripped to obtain a latex having a total sohds contents of from about 10 to 60, preferably from about 25 to 50, percent by weight. As described above, the chlorine content of the chlorosulfonated polyolefin is crucial to the adhesive bonding performance obtained by the method of the present invention. Specifically, it has been determined that chlorosulfonated polyolefins having a chlorine content not greater than about 30 percent have a surprisingly and unexpectedly superior affinity for NPP elastomeric materials. Accordingly, the chlorosulfonated polyolefin of the present invention must have a chlorine content of between about 5 and 30 percent, preferably between about 18 and 26 percent. The sulfur content is typically between about 0.5 and 3 percent, preferably between about 0.9 and 1.6 percent. The chlorosulfonated polyolefin of the present invention typically has a number average molecular weight in the range of from about 50,000 to 150,000, preferably from about 60,000 to 120,000. Chlorosulfonated polyolefins having the chlorine contents specified herein can be utilized without the assistance of the tradi¬ tional aromatic nitroso compounds or their precursors, which have the disadvantages described above. In this regard, the phrase "consisting essentially of is intended to exclude the utilization of the traditional aromatic nitroso compounds or their precursors, as they are deemed to materially affect the basic and novel characteristics of adhesive compositions containing the chlorosulfonated polyolefins of the present invention. The traditional aromatic nitroso compounds or their precursors materially affect the basic and novel characteristics of the present invention because they cause blistering and staining and require high activation temperatures as described above. The chlorosulfonated polyolefins of the present invention may, however, be used in combination with inert auxiliary ingredients such as plasticizers, fillers, pigments, dispersing and wetting agents, surface friction reducing agents, reinforcing agents, and the like, in amounts known to those skilled in the adhesive arts to obtain a desired color, consistency, surface characteristic or weatherability charac- teristic. Examples of inert auxihary ingredients useful in the present invention include plasticizers such as chlorinated paraffins and polymeric polyesters; fillers such as carbon black and clays; pigments such as titanium dioxide and phthalocyanine salts; dispersing agents such as stearic acid and its salts; and surface friction reducing agents such as silicones. Certain reactive auxiliary ingredients may also be necessary for adhesion of the chlorosulfonated polyolefins to substrates other than the NPP elastomers, for example in laminating or bonding NPP elastomers to other dissimilar substrates or polymers, or in flocking NPP elastomer extrusions with polyester flock fibers. The use of reactive auxiliary ingredients may also be utilized to improve environmental service performance such as heat resistance of bonded assemblies. Examples of reactive auxihary ingredients include acid acceptors such as magnesia, litharge and diepoxide acid acceptors; accelerators such as tetramethyl-thiuramdisulfide, dipentamethylene thiuramhexasulfide, and 4,4-dithiodimorpholine; curatives such as dicumyl peroxide; adjunct curatives such as pentaerythritol and m- phenylene bismaleimide; and auxiliary bonding agents such as polyisocyanates (e.g., methylene bis (p-cyclohexylisocyanate)) and heat-reactive phenolic resins. The auxiliary bonding agents are primarily utilized to assist in bonding NPP elastomers to other dissimilar substrates. By achieving adhesion between the present adhesive composi¬ tions and NPP elastomers, a variety of bonding and coating procedures may be carried out. For example, NPP elastomers may be bonded to other NPP elastomers or other solid substrates. NPP elastomers may also be provided with a protective and/or decorative coating. When utilizing the method of the present invention to bond NPP elastomers to other NPP elastomers or to other solid substrates, the present adhesive composition is applied so that it will be in contact with the NPP elastomer during the bonding procedure, after which the NPP elastomer and other substrate are brought into contact with one another at a sufficient temperature and pressure and for a sufficient period of time to effect bonding. Sufficiently elevated temperatures for bonding typically range from about 110° C to 220° C, preferably from about 130° C to 200° C. Sufficient bonding pressures typically range from about 20 to 175, preferably from about 5 to 150 mega pascals (mPa). Sufficient bonding times typically range from about 30 seconds to 60 minutes, preferably from about 3 to 20 minutes, depending on the bonding method and also on the vulcanization rate and thickness of the elastomer being bonded. In the case of bonding an already vulcanized NPP elastomer to itself or other substrates, pressure should be such as to cause between about 2 and 20 percent compression of the NPP elastomer, preferably between about 5 and 15 percent compression. When bonding NPP elastomers to other NPP elastomers, an additional primer or overcoat adhesive is generally not needed. However, when bonding NPP elastomers to other dissimilar substrates, an additional primer or overcoat adhesive composition may be required. When utilized in combination with an additional primer or overcoat adhesive, the present adhesive composition is applied in a manner so that it will be in direct contact with the NPP elastomer during the bonding procedure. For example, in the bonding of a NPP elastomer to metal, a conventional primer adhesive compatible with the metal may be applied to the metal surface, over which the present adhesive composition may be applied as an overcoat so that the NPP elastomer will be in direct contact with the present adhesive composition upon contact with the coated metal surface. Conversely, the present adhesive composition may be applied as a primer adhesive directly to a NPP elastomer, over which a traditional overcoat adhesive compatible with the other substrate may be applied for bonding to the other substrate. One example where the present adhesive composition may be utilized as a primer adhesive is in the bonding of textile fiber in the form of flock to a NPP elastomer. In typical flocking procedures, a polyurethane overcoat adhesive is applied to the primed NPP elastomer so as to bond the flock to the NPP elastomer. The NPP elastomers to be bonded in accordance with the invention may be any of the NPP elastomers described above, and thus the method of the present invention may be utilized to bond identical, similar, or dissimilar NPP elastomers to one another. The NPP elastomers, or other elastomers, to be bonded in accordance with the present invention may be in the vulcanized or unvulcanized state. In the case of unvulcanized elastomer, the bonding temperature is typically sufficient to effect both bonding and vulcanization. Examples of other solid dissimilar substrates useful for bonding to a NPP elastomer in accordance with the invention include metals such as cold-rolled steel, grit-blasted steel, galvanized steel, phosphatized steel, stainless steel, aluminum, treated aluminum, brass, titanium, and the like; and various cured or uncured polar elastomers such as acrylonitrile-butadiene copolymer rubber, chloroprene rubber, polyurethane elastomers, and elasticized and plasticized polyvinylchloride . The method of the invention may also be utilized to apply a protective and/or decorative coating to the surface of a NPP elastomer. The adhesive composition is typically first loaded with the desired pigments, surface friction reducing agents or other additives necessary to obtain a desired effect in the resultant coating. The coating is then applied to the NPP elastomer and exposed to an elevated temperature in the range described above with respect to bonding NPP elastomers, and is most preferably exposed to a temperature in the range from about 120° C to 180° C, preferably from about 130° C to 165° C. The adhesive compositions may be applied to a NPP elastomer or other substrate to be bonded or coated by spraying, dipping, brushing, roll-coating, or the like to form a dry film having a thick¬ ness ranging from about 0.1 to 10, preferably from about 0.2 to 1.5 mils. The adhesive compositions may also be employed in the form of a film or tape by positioning the film or tape between the NPP elastomer and the other similar or dissimilar substrate that is to be bonded. A film or tape may be formed by casting the adhesive composition and solvent or water onto release paper followed by removal of solvent or water as is known in the art. The adhesive compositions of the present invention may be utilized as solvent- or water-based formulations. Typical solvents useful in the present invention include xylene, toluene, ethyl benzene, trichloroethylene, 1,1,1-trichloroethane, perchloroethylene, tetrahy- drofuran, and the like, with toluene or xylene being preferred. Deionized water is preferred for use in aqueous formulations. Auxihary ingredients will be selected to as to be compatible with the particular solvent- or water-based formulation being utilized. The non-volatile content (commonly referred to as total solids content or TSC) of adhesive compositions prepared in accordance with the invention typically ranges from about 1 to 40, preferably from about 8 to 20 percent in the case of solvent-based formulations, and from about 1 to 60, preferably from about 8 to 35 percent in the case of water-based formulations. The following examples are provided for purposes of illustrating the invention and are not to be construed as hmiting the scope of the invention, which is defined by the claims. Example 1 An EPDM elastomer compound was prepared from the following ingredients: Parts bv Weight Ingredient (PBW) Terpolymer of ethylene, propylene, and 100.0 l,4-hexadiene ( a ) Zinc Oxide 5.0 Stearic acid 1.0 Carbon black 80.0 Extender oil 40.0 Sulfur 1.5 Tetramethyl thiuram monosulfide 1.5 Mercaptobenzothiazole 0.5 ( a>NORDEL 1070 (E. I. du Pont de Nemours & Co.) An adhesive overcoat having a non-volatile content of about 17 percent was prepared from the following ingredients using a high speed mixer (KINETIC DISPERSION CO., Laboratory model). Ingredient (PBW) Chlorosulfonated polyethylene (24% Cl 11.20 content) (a > Carbon Black 5.56 Xylene 83.24 ( a ) HYPALON 45 (E. I. du Pont de Nemours & Co.) A conventional metal primer composition (CHEMLOK 205 - Lord Corporation) was applied by dipping (and in accordance with the supplier's recommendations) to vapor-degreased grit-blasted steel coupons (dry film thickness 0.2 mil). The primed coupons were then dipped in the adhesive overcoat detailed above. Dry film thickness for the overcoat was approximately 1.3 mils. Pads of the unvulcanized EPDM elastomer compound prepared above, 1/4" in thickness, were then vulcanized in a press in contact with the adhesive-coated steel coupons for 30 minutes at 160°C. The bonded assemblies were tested by ASTM D429-B (modified for 45° peel angle) at a tensile tester jaw speed of 2" per minute. The resulting bond quality was 100% elastomer-tearing (no interfacial failure) at a pull value to failure of 90 lbs. (average). After one week, the above procedure was repeated for verifi¬ cation using the same experimental overcoat and the same EPDM compound. Again, the test assemblies failed 100% within the elastomer body at a pull value of 100 lbs. (average). Example 2 A second EPDM elastomer compound was prepared from the following ingredients: Ingredient (PBW) Terpolymer of ethylene, propylene, and 100.0 ethylidene norbornene * ) Carbon black 110.0 Extender oil 100.0 Stearic acid 1.0 Zinc oxide 5.0 Mercaptobenzothiozole 0.5 Sulfur 1.5 Tetramethyl thiuram monosulfide 1.5 ( a ) EPSYN 55 (Copolymer Corp.) Bond testing was repeated using the same primer, overcoat and procedure as in Example 1. Results were 100% elastomer-tearing at 98 lbs. pull value (average). Comparative Example 3 An overcoat similar to that described in Example 1 was prepared using HYPALON 40 (35% chlorine content) in place of HYPALON 45. However, to provide comparable dry film thickness after dipping, the non-volatile content of the overcoat was increased from about 17% to about 22% by slightly reducing the amount of xylene. Bonding and testing of EPDM-to-steel assemblies were conducted according to Example 2. Very poor bonding resulted. Pull values averaged 35 lbs. (vs 98 lbs of Example 2) and the mode of failure was 100% interfacial failure (vs 100% elastomer-tearing for the samples of Example 2.) Example 4 Pads 1/8" thick of the same EPDM compound as used in Example 1 were vulcanized in a press for 20 minutes at 160°C. The same adhesive overcoat of Example 1 was painted onto two 1" strips of these pads with a paint brush, and the coated strips were air-dried. The coated strips were laminated (coated face-to-coated face) in a PRECO PRESS at 13,000 lbs platen pressure with a 4" ram (10% compression) and heated for 10 minutes at 138°C. The resulting laminate was cooled and attempted to be delaminated by hand. It was not possible to separate the bonded layers in this way. Rupture of the laminate by peehng using a tensile testing machine then resulted in elastomer-tearing failure (no interfacial failure). Example 5 Generally the same procedure was followed as in Example 4. Adhesives were prepared again using not only HYPALON 45 but also other grades of chlorosulfonated polyethylene of significantly higher specified chlorine contents. These were HYPALON 20 at 29% chlorine, HYPALON 40 at 35% chlorine, HYPALON 30 at 43% chlorine, and HYPALON 48, also at 43% chlorine. The adhesives were made up at a constant ratio of 5.56 parts of carbon black to 11.20 parts of the chlorosulfonated polyethylene in xylene. Non-volatile contents of the several adhesives were in the range of 17-24%, but all adjusted to give approximately the same dry film thickness after dipping. Laminates were prepared using the same vulcanized EPDM and same laminating procedure as in Example 4 except that the heat cycle in this case was 10 minutes at 144°C. Duplicate laminate samples for each adhesive were tested. Results were as follows: Type of chlorosulfonated % % Avg. Pull polyethylene Chlorine Sulfur Value (lbs.) Mode of Failure HYPALON 45 24 1.0 51 100 % elastomer-tearing HYPALON 20 29 1.4 29 25% elastomer-tearing; 75% interfacial failure HYPALON 40 35 1.0 19 100% interfacial failure HYPALON 48 43 1.0 16 100% interfacial failure HYPALON 30 43 1.1 15 100% interfacial failure The above data demonstrates the extremely critical and progressive effect of chlorine content on bonding performance. Example β A white coating formulation was prepared by ball milling the following ingredients. Ingredient (PBW) Chlorosulfonated polyethylene** ) 9.24 Titanium dioxide 7.82 Toluene 82.94 ( a ) HYPALON 45 (E. I. du Pont de Nemours & Co.) Pads of vulcanized EPDM were prepared and cured as in Example 4. The white coating above was painted onto a cured strip of the vulcanized EPDM. After air-drying it was heated in an oven at 153°C for 10 minutes. The resulting cured white coating was very tough and elastomeric and was adhered so strongly to the EPDM substrate as to be almost impossible to remove by scraping with the sharp point of a knife. Example 7 HYPALON 45 in the form of an aqueous dispersion at 40.4% non-volatile content was obtained from SUMITOMO SEIKA CHEMICAL CO. in Japan. This waterborne dispersion was designated by the supplier as CMS LATEX 450. The latex was diluted with deionized water to 17.9% non-volatile content. It was painted onto vulcanized strips of the same EPDM compoτmd as used for Examples 4 and 5. The coated and dried strips were placed face-to-face in a PRECO PRESS under 15,000 lbs platen pressure with 4" diameter ram, and were then heated at 138°C for 10 minutes. The 1" laminated strips were tested for peel strength in a laboratory tensile tester with jaw speed separation of 20" per minute. Peel strength to rupture for two laminates averaged 37.5 lbs with failure 90% in the body of the elastomer and 10% failure interfacial to the adhesive and the vulcanized surface. Example 8 A poly (dimethylsiloxane) emulsion designated DOW CORNING 346 Silicone Emulsion (60% non-volatile content) was blended as a surface friction reducing agent with the CMS LATEX 450 of the preceding example at a level of approximately five parts of silicone emulsion per 95 parts of CMS LATEX 450. The blend was coated onto a strip of the same vulcanized EPDM as used in Examples 4 and 5. After air-drying, the coated strip was heated for 10 minutes at 153°C. The resulting coating was well adhered to the elastomer substrate and showed a very low surface coefficient of friction which can be attributed to the silicone additive.

Claims: dai-ms What is claimed is: 1. A method for achieving adhesion between an adhesive composition and a non-polar polyolefinic elastomer comprising contacting the adhesive composition with the surface of the non-polar polyolefinic elastomer at an elevated temperature sufficient to effect adhesion wherein the adhesive composition consists essentially of a chlorosulfonated polyolefin having a chlorine content of between about 5 and 30 percent. 2. A method according to Claim 1 wherein the non-polar polyolefinic elastomer is selected from the group consisting of ethylene-propylene-diene terpolymers, isobutylene-isoprene copoly¬ mers, and elastomeric trans-polypentene copolymers. 3. A method according to Claim 2 wherein the non-polar polyolefinic elastomer is an ethylene-propylene-diene terpolymer or an isobutylene-isoprene copolymer. 4. A method according to Claim 3 wherein the ethylene- propylene-diene terpolymer is derived from a diene monomer selected from the group consisting of 1,4-hexadiene, ethylidene norbornene, and dicyclopentadiene. 5. A method according to Claim 4 wherein the diene monomer is 1,4-hexadiene or ethylidene norbornene. 6. A method according to Claim 1 wherein the chlorosulfonated polyolefin is selected from the group consisting of chlorosulfonated polyethylene, chlorosulfonated polypropylene, chloro¬ sulfonated ethylene-propylene copolymer, chlorosulfonated trans- polypentene, and chlorosulfonated polyisobutylene. 7. A method according to Claim 6 wherein the chlorosulfonated polyolefin is chlorosulfonated polyethylene. 8. A method according to Claim 1 wherein the chloro¬ sulfonated polyolefin has a chlorine content of between about 18 and 26 percent. 9. A method according to Claim 1 wherein the chloro- sulfonated polyolefin has a sulfur content of between about 0.5 and 3 percent. 10. A method according to Claim 9 wherein the sulfur content is between 0.9 and 1.6 percent. 11. A method according to Claim 1 wherein the chlorosulfonated polyolefin has a number average molecular weight in the range from about 50,000 to 150,000. 12. A method according to Claim 11 wherein the molecular weight is in the range from about 60,000 to 120,000. 13. A method according to Claim 1 wherein the adhesive composition also contains an inert auxihary ingredient selected from the group consisting of plasticizers, fillers, pigments, dispersing and wetting agents, surface friction reducing agents, and reinforcing agents. 14. A method according to Claim 13 wherein the plasticizers are selected from the group consisting of chlorinated paraffins and polymeric polyesters, the fillers are selected from the group consisting of carbon black and clays, the pigments are selected from the group consisting of titanium dioxide and phthalocyanine salts, the dispersing agents are selected from the group consisting of stearic acid and its salts, and the surface friction reducing agents are silicones. 15. A method according to Claim 1 wherein the adhesive composition also contains a reactive auxiliary ingredient selected from the group consisting of acid acceptors, accelerators, curatives, adjunct curatives, and auxihary bonding agents. 16. A method according to Claim 15 wherein the acid acceptors are selected from the group consisting of magnesia, litharge and diepoxide acid acceptors; the accelerators are selected from the group consisting of tetramethylthiuramdisulfide, dipentamethylene thiuramhexasulfide, and 4,4-dithiodimorpholine; the curative is dicumyl peroxide; the adjunct curatives are selected from the group consisting of pentaerythritol and m-phenylene bismaleimide; and the auxiliary bonding agents are selected from the group consisting of polyisocyanates such as methylene bis(p-cyclohexylisocyanate) and heat-reactive phenolic resins. 17. A method according to Claim 1 wherein the non-polar polyolefinic elastomer is bonded to another non-polar polyolefinic elastomer. 18. A method according to Claim 1 wherein the non-polar polyolefinic elastomer is provided with a protective and/or decorative coating. 19. A method according to Claim 1 wherein the non-polar polyolefinic elastomer is bonded to another dissimilar substrate. 20. A method according to Claim 19 wherein the adhesive composition is utilized in combination with an additional primer or overcoat adhesive composition.

Inventors: SEXSMITH FREDERICK H, SEXSMITH, FREDERICK, H.
Applicants: LORD CORP, LORD CORPORATION
Application year: 1994
Main classification: C09J5
IPC codes: C08J5, C09J5, C09J123